Glasgow Embedded / Glasgow - History

applet.interface.spi_master: remove length restrictions.

These are however not removed downstream (mostly from memory-25x
applet) because they are useful for progress indication.

Also, this implementation does not take advantage of pipelining for
transfers longer than 64K.

applet.interface.spi_master: redesign command set to be like jtag_probe.

The JTAG probe applet has a very nice orthogonal command set, more
applets should be like it. In the future, the SS# line should be
changed to be an ordinary aux signal, and all dependent applets with
aux signals in registers should be redesigned to use those.

applet.interface.jtag_probe: disable autoflush.

Potentially increases performance on large sequences of pipelined
reads (not that we have a good way to submit such sequences yet.)

applet.interface.sbw_probe: allow clocking TCLK via sideband.

applet.interface.jtag_probe: add explicit support for sideband signals.

One example of a sideband signal is TRST#, already present, but other
ones are also useful, for example SRST#, device programming signals
like PROGRAM#, and also alternative transport layers, which might use
these sidebands internally.

A number of pulse_trst() calls has been removed from other applets
on the grounds that the TRST# driver (if TRST# is present) is enabled
by default, and so TMS-driven reset should be sufficient for most
use cases. The reset argument to JTAGProbeApplet.run() may later be
exposed via a command line argument as well, in case some devices
turn out to need an explicit TRST# pulse.

applet.interface.sbw_probe: bit reverse JTAG ID.

Texas Instruments WHYYYYYYYYYYYY

applet.interface.jtag_probe: allow shifting TDIO over 65535 bits.

This comes up in SVF files, e.g. SVF files generated by nextpnr
produce TDIO shifts of 100000 bits.